20. he took the calf which they had made, and burnt it in the fire, &c.--It has been supposed that the gold was dissolved by natron or some chemical substance. But there is no mention of solubility here, or in De 9:21; it was "burned in the fire," to cast it into ingots of suitable size for the operations which follow--"grounded to powder"; the powder of malleable metals can be ground so fine as to resemble dust from the wings of a moth or butterfly; and these dust particles will float in water for hours, and in a running stream for days. These operations of grinding were intended to show contempt for such worthless gods, and the Israelites would be made to remember the humiliating lesson by the state of the water they had drunk for a time [NAPIER]. Others think that as the idolatrous festivals were usually ended with great use of sweet wine, the nauseous draught of the gold dust would be a severe punishment (compare 2Ki 23:6, 15; 2Ch 15:16; 34:7).

JFB.